Lesser minion gold

Hello everyone, Yesterday i played Morgana jungle and was unpleasantly surprised to see the amount of gold income upon minion kills. I got only 11 golds for melee minion and only 4 golds for ranged minion. I thought it was some new Riot experiment on preventing junglers from stealing gold from lane players, but then I took a replay and was shocked to see that opponent WW took regular 21/14!!! LOL? So i got 10 gold deduction which WW unrestricted enjoyed. And now I am just interested does some of the game item/rune cause gold deduction? To suppress any doubts: even though some may think that it is only a "display bug", it was not - I checked my gold balance on every minion hit and it was calculated with the exact amount of what was displayed on the screen. Here is one screenshot: https://postimg.cc/image/4fzhwkoaj. Anyway, game ended 3vs5 win for them so I wasn't bothered too much. But my concern is that if some champs or items are diminished in oposit to other players, I would really need some guideline for that.

Thanks!